Colloquium d'informatique

2012-2013 - Campus Jussieu

Séminaire de prestige en recherche informatique. Invitation de grands noms du domaine, visant un public large.

Fluidization of discrete event models or a marriage between the discrete and the continuous

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Formal discrete event, hybrid and continuous representations of systems provide “views” of their structure and behaviour in potentially many fields of application. In information technology (also in epidemiology, biochemistry, etc.), discrete event models are frequently “adequate” from a descriptive point of view (idea of faithfulness or accuracy), but the so called “state explosion problem” may eventually make their consideration not very practical.

Technically speaking, the fluidization of a discrete event model can be viewed as a (partial) relaxation of its state “from the integers into the reals”. From a more conceptual perspective, it can be viewed as a change of the point of view “from the individuals to populations” (i.e., single agents in a given internal state would not be distinguishable). The goal of such kind of relaxation or change of the point of view may be to reduce the computational complexity of the algorithms for certain analysis and synthesis problems, eventually to make decidable some properties. Of course, some price should be paid for that, and certain properties cannot be studied on the hybrid or continuous derived model, while for other properties only “approximate” answers can be obtained. As an important advantage, the more populated the system is, usually the more accurate are the answers obtained and the bigger are the computational savings obtained.

Taking Petri Nets as a well-known and expressive family of formalisms for discrete event “views”, the presentation will introduce the fluidization and focus on new analysis and synthesis possibilities, as much as on the price paid for that.

Orateur(s) : Manuel Silva, University of Zaragoza
Public : Tous
Date : Tuesday 25 November 2014 at 18:00
Lieu : Amphithéâtre Astier, Esclangon Building